Two of my favorites for drinking & cooking, one from Ontario, one from Germany
http://www.lcbo.com/lcbo/product/strewn-two-vines-riesling-gewurztraminer-vqa/467662#.WZV8jlGGPIU
http://www.lcbo.com/lcbo/product/moselland-bernkasteler-kurfurstlay-riesling/15875#.WZV80lGGPIU

I haven't made this particular recipe, but for other white sangrias I've made, something light to medium bodied and brightly acidic works best. Vermentino and sauvignon blancs have worked well for me, but these are semi-random based on convenience -- tons of others I'm sure would be at least as good. The additives in the sangria will swamp out subtle flavors so it's fairly forgiving and also not worth putting something expensive in. Aim for something that's pleasant if a bit boring to drink on its own.